Reforming process and catalyst therefor



Patented Sept. 23, 1952 REFORMING PROCESS AND CATALYST THEREFOR VladimirHaensel, Hinsdale, Ili., assignor to Uni versal Oil Products Company,Chicago, 111., a

corporation of Delaware No Drawing. Application Novemberlfi, 1948,Serial N0. 60,381

Claims. (01. 196 -50) a This invention relates to a. reforming processand to the manufacture of catalysts for use therein.

The term reform'ing is well known in the petroleum industry and refersto the treatment of gasoline fractions to improve the anti-knockcharacteristics thereof. The gasoline fraction may be a full boilingrange gasoline having an initial boiling point within the range of fromabout 50 to about 100 F. and an end boiling point within the range offrom about 350 to about 425 F., or it may be a selected fraction:thereof which usually will be a higher boiling carbons which usually areof straight chain or slightly branched chain structure, as Well asvarying proportions of aromatic hydrocarbons. In order to obtain bestresults in reforming operations, it is desired to dehydrogenate thenaphthenic hydrocarbons to produce aromatics, to cyclisize the straightchain parafiinic hydrocarbons to form aromatics, as well as to effect acontrolled type of cracking which is selective both in quality andquantity. In addition, various other concomitant reactions occur such asisomerization, hydrogen transfer, etc.

The cracking or splitting of carbon to carbon bonds is one of theimportant factors in a successful reforming process. Controlled-orselective cracking is highly desirable since such cracking will result"in a product "o'f improved anti-knock characteristics. In general, thelower molecular weight products have higher octane numbers, and thus afinal gasoline productof lower average molecular weight willgusuallyhave a higher octane rating. Furthermore, during the cracking reaction,isomerization or other molecular rearrangement occurs which also resultsin products having higher anti-knock characteristics. The selectivecracking is also of particular advantage when the charging stockcontains components boiling above about 400 F. in order to convert thesecomponentsto fractions boiling below about 400 F. It is thus seen thatthe selective cracking results not only in an improved quality productbut also in an increase in quantity of the desired products.

' However, the cracking must be selective and must not result in thedecomposition of the normally liquid hydrocarbons substantially orcompletely into normally gaseous hydrocarbons. The

desired selective crackin generally comprises the splitting of a higherboiling hydrocarbon molecule into two molecules both of which arenormally liquid hydrocarbons. To a lesser ex; tent it comprisestheremoval of methyl, ethyl and, to a still lesser extent, propyl groups,in the form of methane, ethane and propane. How'- ever, the removal ofthese radicals is controlled so that not more than one or possibly twoof such radicals are removed from a given molecule, For example, decanemay be reduced to two pentane molecules, heptane to hexane, nonane tooctane or heptane, etc. On the other hand, uncontrolled or non-selectivecracking will result in the'decomposition of normally liquidhydrocarbons into normally gaseous hydrocarbons as, for example, by thecontinued demethylation of normal heptane to produce '7 molecules ofmethane. I 7

Another important objection to non-selective or uncontrolled cracking isthat this type of cracking will result in the more rapid'formationshould thecatalyst activity be destroyed, it will i be necessary'to shutdown the unit to remove the old catalyst and replace it with newcatalyst.

Another important feature in successful reforming processes is thematter of hydrogen production and consumption. Investigation has shownthat the presence of hydrogen in the reforming zone further tends todecrease the amount of carbonaceous deposit on the catalyst. Reformingprocesses effected, in the presence of hydrogen are known ashydroformingif. In view of the fact thatthe cost of hydrogen is quitehigh, it is essential that there be no netconsumption of hydrogen or, inother words, at least as much hydrogen must be produced in the processas isconsumed therein. I

In one embodiment the present invention relates to a process forreforming a gasoline fraction which comprises subjecting said fractionto contact at reforming conditions with a catalyst prepared by combininga halogen with alumina in an amount of from about 0.1 to about gasolinefraction which comprises subjecting said gasoline fraction to contact ata temperature of from about 600 to about 1000 F, a pressureof from about50 to about 1000 pounds per square inch and a weight hourly spacevelocity of from about 0.5 to about in the presence of a'catalyst asherein set forth.

In another specific embodiment the present invention relates to a methodof manufacturing a catalyst which comprises combining a halogen withalumina in an amount of from about 0.1 to about 8% by weight of saidalumina on a dry basis, commingling therewith a platinumcompound-ammonium hydroxide solution in an amount to form a finalcatalyst containing from about 0.01 to about 1% 'byiweight of platinum,and heating the composite in air at a temperature of from about 500 toabout 1000 F.

The .use of platinum as a catalyst for .conversion processes has been oflimited commercial acceptance because of the high cost of the catalyst.The present invention is based on the discovery that exceptionally goodcatalysts may be prepared to contain very low concentrations ofplatinum. While these catalysts may contain larger concentrations ofplatinum, which may range up to about 10% by weight or nore of thealumina, it has been found that exceptionally good catalysts may beprepared to contain as low as from about 0.01% to about 1% by weight ofplatinum, Catalysts of these low platinum concentrations areparticularly preferred in the present invention because of theconsiderably lower cost of the catalyst. It is well known that platinumis very expensive and any satisfactory method of reducing the amount ofplatinum considerably reduces the cost of the catalyst and thus enhancesthe attractiveness .of the catalyst for .use in commercial processes.

However, in order to obtain improved results with these low platinumconcentrations, it is necessary that a particular type of supportingcomponent must be composited with the platinum. It has been found thatalumina .shows unexpectedadvantages for use as a supporting componentfor the low platinum concentrations, apparently due to some peculiarassociation of the alumina with the platinum, eitheras a chemicalcombination or as a physical association. It has been found that thespecificcombination of alumina and low platinum concentration, not onlyto be a very active catalyst, but also to have a long catalyst life;that is, the catalyst retains its high activity for long periods ofservice. After these long periods of service, the catalyst may show adrop in activity and it has further been found that the particularcombination of alumina and platinum renders the catalyst susceptible toready regeneration.

As another essential feature of the present invention, impregnation ofthe alumina must be distribution of the platinum in or on the aluminaparticles is obtained. Usually this uneven distribution comprisessurface coating, that is the platinum compound is distributed only onthe surface of the particles and not evenly throughout the mass. Byefiecting the impregnation in the presence-of ammonium hydroxidesolution, even distribution of the p'latinumthroughout the aluminaparticles is obtained.

A particularly satisfactory method of impregnating the alumina comprisesthe use of an aqueous solution of chloroplatinic acid. In a preferredembodiment, the aqueous solution of chloroplatinic acid is commingledwith an ammonium hydroxide solution and the mixture is added to aluminaparticles. In another embodiment, the ammonium hydroxide solution may beadded to the alumina particles and the chloroplatinic acid solution isthereafter added to the mixture. In still another embodiment, thechloroplatinic acid solution may be added to the alumina particles andthe ammonium hydroxide solution is thereafter added. In any event, themixture is allowed to stand, preferably with or after suitableagitation; so that thorough mixing is obtained and even distribution ofthe platinum throughout the alumina particles is effected.

In its preferred embodiment, the present invention is directed tothe useof ammonium :hydroxidesolution in order. to avoid the formation, uponvcommingling with chloroplatinic acid, of ammonium chloroplatinatebecause ammonium chloroplatinateis insoluble in aqueous solutions andwill not result in even distribution throughout the alumina particles.Thus, .an ammonium salt as, for example, ammonium chloride, cannot beused in place of ammonium hydroxide .because upon commingling ofammonium chloride with chloroplatinic acid a precipitate or ammoniumchloroplatinate is obtained. Even upon heating or upon the addition ofammonium hydroxide, .the precipitate will not be redissolved to form aclear solution. However, in some cases, both the addition of ammoniumhydroxide and heating will redissolve the precipitate to form a clearsolution and, in such cases,.the use of arm monium chloride may beemployed in conjunction with both ammonium hydroxide and heating.

With proper selection of the chloroplatinic acid solution and ofammonium hydroxide solution, commingling of these solutions will notform a precipitate and, therefore, will not form ammoniumchloroplatinate. Applicant is not certain as to the exact chemicalformula of the compound formed but it is believed to be[Pt(NI-I3)2C12]C12. In any event it is apparent that the clear solution;formed upon the mixing of ammonium hydroxide .with chloroplatinic acidsolution is dififerent than theammonium chloroplatinate precipitateformed upon the addition of'ammonium chloride to chloroplatinic acidsolution. If ammoniumv chloroplatinate solution is formed.ashereinbefore set forth, or due to the use of a too highly concentratedsolution of chlcroplatinic acid, the ammonium chloroplatinate solutionmay be redissolved to form the clear solution which is no longerammonium chloroplatinate and apparently is the compound 'hereinbeforeset forth. The difference between the two compounds is further evidencedby the fact that the addition of carbonate ions as, by the addition ofsodium carbonate, will not form a precipitate in the case of the mixtureof ammonium chloride with chloroplatinic acid upon heating. but willform a precipitate in the case of thesolution of ammonium hydroxide withchloroplatinic acid 'upon heating;

To "furtherimprove these catalysts, it is an essential feature ofthepresent invention that the final catalyst contains halogen ions in aspecific concentrationb It has been found, and will be shown in thefollowing examples, that the presence of halogen ions within a specificrange effects a considerable improvement in the catalyst. It is believedthat the halogen enters into some chemical combination or loose complexwith "the alumina and/or platinum, and therebyserves to improve thefinal catalyst.

' While any of the halogen'ionswill serveto effect improved results;fluoride ions are particularly preferred. Next in order are the chlorideionsywhile the bromide and iodide ions are generally less preferred. Itis understood that, while all of these halogens will serveto effect animprovement, they are not-necessarily equivalent.

"In still another essential feature of the present invention the finalcomposite of alumina platinum compound and combined halogen is calcinedin the presence of an oxygen-containing gas, particularly air, at atemperature of from-about 500 to about 1000 F. for a period of 2 to 12hours or more. As will'be' shown in the following examples, calcina-tionin the presence of air results in a-final gasoline product of higheroctane number than is obtained'when the catalyst only-is calcined in thepresence of a reducing atmosphere. In still another embodiment of theinvention, the 'flnalcomposite may be reduced in i the presence ofhydrogen and then calcined in the presence of air, both the reductionand calcination being efiected at temperatures withinthe range of fromabout 500 to about 1000 F.

In apreferred embodiment of the'invention,

the'alumina is formed into particles'of uniform size and shape priorto'impreg'nation with the platinum compound. As another particularfeature of this embodiment, the alumina particles of uniformsize andshape are subjected to calcination at a temperature above l000 andpreferably within the range of fromabout'1000 to about 1400 F. for aperiod of l to 8 hours or more. The temperature and time of heating" arecorrelated; 'that'is, shorter times are er'nployed with highertemperatures and longei'times are employed with lower temperatures. Onthe other hand, the final composite "containing platinum compound mustnot be heated at a temperature above.l000 F; and preferably is calcinedinai-r at a temperature of 'fromabout 500 to about 1000.".iF. for aperiod of 2 to 12 hours or more as hereinbefore set forth. s g

The catalyst of the present inventionimay be prepared in anysuitable-manner. A particularly preferred method is to prepare aluminaby adding a suitable reagent, such 'asamm'onium hydroXide, ammoniumcarbonate, etc. to a salt of aluminum such as aluminum chloride,aluminum nitrate, aluminum acetate; etc. in an amount to form aluminumhydroxide which, 'upon drying is converted to alumina and, in theinterest of simplicity, the aluminum hydroxide is referred to as aluminain the-present specification and claims in order that the percentages"are based on the alumina free of combined .water. It has been foundthat aluminum chloride is generally preferred as the aluminum salt, notonly for convenience in subsequent washing and filtering procedures, butalso because it appears to give best results.

, After the alumina has been formed, it is vention this Washing may beselective to retain chloride ions in an amount of from about 0.2% toabout 8% by weight of the alumina on a dry basis. In accordance withthis method ofpreparing the catalyst, the chloride ions are obtainedfrom the original aluminum chloride and are retained in the alumina,thus avoiding the necessity of adding the halogen ions in a later stepof catalyst preparation. However, it generally is difficult to controlthe washing procedure to retain the desired amount of halogen ion and,for this reason, it usually is preferred to wash the alumina to removesubstantially all ofthe chlorine ions and thereafteradd' the halogenions in a controlled'amount. The addition of the halogen ions in thismanner permits better 'con' trol of the amount of halogen'being added;In

another embodiment of the invention, the Washing. may be selective toretain the chloride ions'in an amount constituting a portion of thetotal halogen desired, and the remaining-portion of the halogen is thenadded in a subsequent step.

In this method, the halogen ion-amay comprise the same halogen ora-mixtur e of two different halogens, as for example; chlorineandfluorine.

Alumina prepared in the above manner, after washing and filtration, isgenerally recovered as a wet cake. In a preferred embodiment of thepresent invention, the halogen is added at this stage of the catalystpreparation, the composite is dried to reduce the same to' amoisture'con' tent of about 30%, which generally requires dry ing at atemperature of from about200 to about 500 F. for a period of about 2 to24 hours or more,

and the composite is formed" into particles of uniform size and shape asby pillingfextrusion or other suitable methods. In another embodiment,the alumina may be formed into particles of uniform size and shape andthe halogen thereafter added. In still another embodiment the halogenand platinum'additionmay beeffected prior to forming the compositeintoparticles' of uniform size and shape.

Regardless of the stage of catalyst prep'ar'a tion at'which the halogenis add edpthe halogen may be incorporated therein in'any suitablemanner. However, the halogen must'be added in a'form which will readilyreaetf'with the alumina in ordertoobtain-thedeSired results and .alsomust not leave undesired deposits in the catalyst. 'A preferred methodof adding the halogen is in the form of an acid, such as hydrogen'fluoride, hydrogen chloride, hydrogen bro' mideand/or hydrogeniodidej"Hydrogen fluoride is preferably added as an aqueous solution'for easein handling and for control of the specific amount to be added. Anothersatisfactory source to be used for adding the halogen" is the volatilesalts, such as ammonium" fluoride, am monium chloride, etc. The ammoniumions will be removed during the subsequent heating of'the catalyst and,therefore, will not leave undesirable deposits in the catalyst. In stillanother method, the halogen may be added as fluorine, chlorine, bromineor iodine but, in view of the fact that the halogens are normally moredimcult to handle, it is generally preferable to utilize them in theform of a solution for ease in handling. In some cases, the inclusion ofcertain components will not be harmful but may be beneficial, and inthese cases the halogen may be added in the .form of suitable salts.

The concentration of halogen ion in the finished catalyst will be withinthe range of from about 0.1% to about 8% by weight of the alumina on adry basis. The fluoride ion appears to be more "active and thereforewill be used within the range of from about 0.1% to about 3% by weightof the alumina on adry basis. The chloride ion will be used within therange of from about 0.2% to about 8% and preferably from about 0.5 toabout 5% by weight of the alumina on :a dry basis. It has been foundthat halogen concentrations below these lower limits do not give thedesired improvement and, on the other hand, concentrations of halogenabove the upper limits adversely affect the selectivity of the catalyst,thus catalyzing side reactions to an extent 'greater than desired.

vAs hereinbefore set forth, it is essential that the platinum compoundbe incorporated in the alumina or alumina-halogen composite in thepresence of ammonium hydroxide to obtain uniform distribution of theplatinum throughout the catalyst mass. In a preferred embodiment of thepresent invention, the alumina, either with or without halogen, isformed into particles of uniform size and shape prior to the addition ofthe platinum compound. 'When the alumina is to be formed into particlesof uniform size and shape by pilling, the wet alumina cake, with orwithout halogen, is dried at a temperature of from about 200 to about500 F. for a period of from about 2 to 24 hours or more. The partiallydried cake is ground and a suitable lubricant is added, such as stearicacid, rosin, hydrogenated coconut oil, graphite, etc., after which thecomposite is formed into pills in any suitable pelleti-ng machine.Particularly satisfactory particles comprise cylindrical pills of a sizerangingfrom about 1 6" X 1%" to 4! X A," or thereabouts. :Pills ofuniform size and shape mayalso be formed by extrusion Or other suitablemethods. As herein-before set forth, it is an essential feature of thepreferred embodiment of the present invention that the pills, prior tothe addition of the platinum compound, are calcined at a temperatureabove 1000 F. In some cases, the lubricant will be removed during thehigh temperature heating. In other cases as, for example, when graphiteis used as the lubricant, the lubricant will not be removed during theheating step.

In accordance with the invention, the alumina or alumina-halogenparticles are impregnated with a platinum compound-ammonium hydroxidesolution in order to obtain even distribution of the platinum compoundthroughout the preformed particles. This has not been obtained in theabsence of the ammonium hydroxide solution as has been clearly,demonstrated .by impregnating alumina pills in the presence and absenceof ammonium hydroxide solution. Pills prepared in both of these methodshave been treated with hydrogen sulfide to fix the platinum compound asthe sulfide which is-a dark color. Upon splitting open, it was observedthat the pills impregnated in the presence of ammonium hydroxidesolution were of the same color throughout, whereas the pillsimpregnated in the absence of ammonium hydroxide were of a dark color onthe outside and of a light color on the inside.

A possible explanation of the benefits obtained with the evenlydistributed catalyst pills is that the platinum molecules are spreadthroughout the pills and therefor are spaced further apart and will notresult in the formation of large crystals of platinum. On the otherhand, in the surface coated pills, the platinum molecules are spacedcloser together and therefore may form large crystals. Another advantagsto the even distribution of the platinum throughout the catalyst is thatthe platinum in association with hydrogen tends to reduce carbonformation and thus when the platinum is distributed evenly throughoutthe catalyst this efiect is enhanced. 0n the other hand, when theplatinum comprises only surface coating, the center of the pill maycatalyze carbon formation because of not being able to benefit from thetendency of the platinum and hydrogen to reduce carbon formation.

Another important advantage to the even distribution of platinumthroughout the catalyst from a commercial viewpoint is that a smallervolume of catalyst is required for a given plant capacity than in thecase of the surface coated pills. This reduces the cost of the plantequip- I ment by permitting the use of smaller vessels and reducedsupporting structures, as well as lower catalyst shipping charges, etc.Still another advantage from a commercial viewpoint is, because of thehigh cost of platinum, it is advantageous to incorporate the platinumcompound at the later stages of catalyst preparation in order thatplatinum will not be lost during subsequent handling and treating of thecatalyst. Thus, it is preferred that as'much of the necessary mixing,washing, filtering and heating steps be done before the platinumcompound is incorporated. Further, this permits effecting the desiredhigh temperature heating of the alumina pills at temperatures above1000" F. without also subjecting the composite containing platinum tothese high temperatures.

As hereinbefore set forth, impregnation of the alumina particles withthe platinum compound is effected in the presence of an ammoniumhydroxide solution and in a preferred embodiment an aqueous solution ofchloroplatinic acid is commingled' with ammonium hydroxide solution inproportions to form a mixed solution having a pH within the range offrom about 5 to about 10 and preferably within the range of from about 8to about 10. This mixture is then commingled with the calcinedalumina-halogen pills in the preferred embodiment of the invention. Ashereinbefore set forth, in another embodiment of the invention, theammonium hydroxide solution or the chloroplatinic acid solution may beadded to the alumina and the other solution subsequently added thereto.

Regardless of the order of adding the ammonium hydroxide andchloroplatinic acid solutions, a particularly advantageous method ofcommingling the solution with alumina, is to soak the alumina-halogenpills in an aqueous solution of chloroplatinic acid and ammoniumhydroxide, and then heating the mixture; In this embodiment of theinvention the alumina pills may be added to either 'a hot or coldsolution of chloroplatinic acid-ammonium hydroxide. In anotherembodiment of the invention, the alumina pills are soaked in an aqueoussolution of chloroplatinic and ammonium hydroxide, and the water andresidual ammonium hydroxide are removed by decantation, filtering or thelike. In this embodiment of the invention, the chloroplatinic acidsolution is preferably utilized as a hot solution.

After the chloroplatinic acid solution has been incorporated in thealuminalpills and the water and residual ammonium "hydroxide removedtherefrom, the composite is dried at a tempera ture of from about 200 toabout 500 F. fora. period of about 2 to 24 hours or'more and thecomposite is then calcined in air at a temperature of from about 500 to1000F. but, as heroin before set forth,' shall not exceed'1000 F. Instillanother embodiment of the invention, the composite after drying maybe reduced in the presence of hydrogen at a temperature of from about500 to about 1000 F. and then calcined in the presence of air atei-temperature of from about 500 to about 1000 F.

In the embodimentof the invention wherein pilling of the catalyst is noteffected until after the platinum compound has been added thereto, themass is dried at a'temperature of about 200 to' 500 F. for 2 to 24 hoursor more and then calcined at a temperature not'to exceed 1000 F. Ashereinbefore set forth, after the platinum compound has beenincorporated into the catalyst the composite should not be heated to'atemperature in excess of 1000 F. I

Although the catalyst of the present invention will have a long life, itmay be necessary to regenerate the catalyst after long periods ofservice. The regeneration maybe effected by treatment with air-or otheroxygen-containing gas to burn carbonaceous deposits therefrom. Ingeneral, it is preferred to control the regeneration temperature not toexceed 1000 F. and pref erably the regeneration is effected at a temperature' within the range of from about 600 to 'about'800"F. j Thereforming process will be effected at a temperature within the range offrom about 600 to about 1000 F., a pressure within the range of fromabout 50 to about 1000 pounds per square inch and at a weight hourlyspace velocity of from about 0.5 to about 10. The weight hourly spacevelocity is defined as the weight of oil per hour per weight of catalystin the reaction zone.

Hydrocracking reactions are favored at temperatures 'within the rangeoffrom about 600 to about 700 F. and at pressures within' the range offrom about 500 to about 1000 pounds or more. I Hydrocracking is definedas cracking. or splitting of carbon bonds accompanied by saturation ofthe fragments so formed by'hydrogen present in the reaction zone' and,in accordance with the present invention, the hydrocracking will beselective both in. quality and in quantity as hereinbefore set forth. Onthe other hand, aromatizatio'n reactions are favored at temperatureswithin the range. 'of from"about 650 to 1000 F. and at lower pressureswithin therange of from about 50 pounds to about 400 pounds per squareinch. It is an essential feature of the present invention that thetemperature, pressure and space velocity are correlatedto producethedesired aro'matization and selective hydrocracking. The exacttemperature, pressure and space velocity to be used in anyv givenoperation will depend upon the particular gasoline fraction beingtreated and the particularproducts desired.

However, itusually will be preferred to introduce hydrogen from anextraneous source, generally. at the beginning of the operation, and torecycle hydrogen within theprocess in order to bees sured ofa-suflicient hydrogenatmosphere in the reaction zone-.- The hydrogenpresent in the reaction zone will bewithin the range .offrom about 0.5to about 10 mols of hydrogen per mol of hydrocarbon. In some casesthegas to be recycled will contain hydrogen sulfide, introduced with thecharge or .;liberated from the catalyst, and it is-withinthe scope ofthe present invention to treat the hydrogen containing gas to remove,hydrogen sulfide or other impurities before recycling the hydrogenwithin the process.

The process of the present invention may be effected in any suitableequipment. A particularly suitable process comprises the well knownfixed bed system in which the catalyst is disposed in a reaction zoneand the hydrocarbons to be treated are passed therethrough in eitherupward or downward new- The products are fractionated to separatehydrogen and to recover the desired products. As hereinbefore set forth,

the hydrogen preferably is recycled for further use in the process.Other suitable units in which the process may be effected include thefluidized type process in which the hydrocarbons and catalysts aremaintained in a state of turbulence entinvention, but not withtheintention of unduly limiting the same, F

' EXAMPLE I A catalyst was prepared accordance with the presentinvention by addingammonium hydroxide to aluminum chloride hexahydrat toform aluminum hydrate. j The resultant aluminum hydrate was washed verythoroughlyinorder to reduce the chloride content to below 0.1 by weighton a dry basis. Thiswashing entailed 6 separate washes with largeamounts of waterpontaining a small amountof. ammonium hydroxide and afinal wash. withwvater', with intervening filtering betweeniwashes. Anaqueous solution of hydrogen fluoride was added tothe washed alumina inan amount of about 0.3 by weight of alumina on" a dry basis. Thealumina-fluorine composite was dried ata' temperature of about340 F- for8-10 hours in order to reduce the moisture content to about 30%.

The partially dried alumina was ground, Stearotex added as lubricant,and'then pilled in a Stoke-s pelleting machineto form cylindrica1pills,0f..- x A", in size. The pills were: then calcined iniairi'at'atemperature of about;

932 for .6 hours to remove the lubricant and then further calcined at atemperatur'e of about 1200 F for- 3 hours. Concentrated ammonium hy--droxide'so'lution ('30'% was added 1702!. dilute so-' lution ofchloroplatinic acid (0.1 grams of chloroplatinic-acid in 10100. ofwater). This solution 1 1- produced no precipitate but remained a clearyellow solution, having a pH of about 9. The alumina pills were soakedin the chloroplatinic acidammonium hydroxide solution, the quantitiesbeing controlled to form a final catalyst containing 0.3% by weight ofplatinum. The mixture was then heated on a steam bath, after which thecatalyst was dried at 230 F.'for 3 hours and calcined in air at 932 F.for 3 hours.

Another catalyst was prepared in substantially the same manner exceptthat the final calcination in air at 932 F. was omitted and the catalystinstead was reduced in hydrogen at 932 F. for 3 hours.

Still another catalyst was prepared in substantially the same mannerbutwas first reduced with hydrogen at 932 F. for 3 hours and thencalcined in air at 932 F. for 3 hours. These catalysts were used for thereforming of a Mid-Continent straight-run naphtha having a boiling rangeof from 180 to 400 F., at a temperature of about 850 F. a pressure of500 pounds per square inch, a weight hourly space velocity of about 2and a hydrogen to hydrocarbon ratio of 3:1. The results of these runsare indicated in the following table.

Table I.

Catalyst 1, Catalyst 2, me Charge Calcined Reduced Egg g in air with Hecmgd m all Reiormate yield, 90.6 94.4 90.7 weight percent of 90.5 94.391.1 22-2 22-2 22-2 Floctanenumber (Re search method). F2 octane number77.8 7.18 26.8 (A. S. T. M. motor 34.6 77.7 72.0 16.5 method). 77. 5 70.i 76. 5 Aromatics, weight per- 6 6 6 cent charge 26:6 45.8

The results reported in the above table comprise three successive hourtest runs for each catalyst. In this way, any tendency of the catalystto lose activity or to increase in either aromatization or hydrocrackingproperties is observed.

It will be noted from the above data that the catalyst calcined inair'icatalyst 1) produced a reformate having a much higher octane numberthan that produced in the catalyst which only was reduced in hydrogen(catalyst 2). Particular attention is called to the aromatic content ofthe product, which it will be noted remains substantially constant withcatalyst 1 but dropped from-39.2 to 26.6 with catalyst 2. It also willbe noted that following. the reduction in hydrogen with caicination inair restored part of the desirable properties of the catalyst asevidenced by catalyst 3; v

EXAMPLE II This example illustrates the eiiectof final calcinationtemperature. A batch, of catalyst was prepared to contain 0.3% byweight. of' combined fluorine and 0.3% by weight of platinum. Thecatalyst was pilled after the platinum was incorporated therein...Aportion of thepills was calcined at 932 F.for 3- hours. Another portionof the pills was calcined at 1337 F; for 3 hours. These catalysts whenused for the reforming of. a Pennsylvania straight-run naphtha at a l2temperature of about 873 F., pressure or 500 pounds per square inch, aweight hourly space velocity of about 2 and a. hydrogen to hydrocarbonation of 3:1 gave the results in Table II.

It will be noted from the data in the above table that the catalystcalcined after the platinum was compositedtherewith at a temperature of1337 F. had decreased aromatization and increased hydrocrackingproperties as compared to the catalyst calcined at 932 F. This isillustrated in the lower yield, the decrease in arcmatics and in thehigher percentage of material boiling below 212 F. As set. forth in thepresent specifications, this amount of hydrocracking. is undesirablebecause it represents a loss of charging stock to lower boiling materialand particularly to gaseous products which cannot be used in gasoline.

EXAMPLE III Another batch of catalysts was prepared in substantially thesame manner as hereinbefore set forth except that the composite ofalumina and fluorine was dividedinto two portions. One portion wascalcined. at 932 F. for 3 hours and the other portion was calcined at1337" F. for 3 hours. Platinum was thereafter vcomposited separatelywith the two portions, following which the portions werev separatelydried, lpilled and calcined at 932 F. for 3 hours These portions wereused in separate runs to reform aMid-Continent straight-run naphthaunder substantially the same conditions recited in Example II, and gavethe following results.

Table III Catalyst 6, Catalyst 7, G'alcined' calcined at 932 F. at 1337"F Stabilized reiormate yield, Volume percent of charge 92. 5 89. 6Aromatics, weight peroentof charge 44.- 7 44. 5 F1 octane number 83. 78S. 8 F2 octanenumber 76. 6 8D. 1 Percent of material boiling below 212based on total liquid product 28. 2 39. 6

Another batch oilcatal'yst'was prepared insubstantially the same manneras' hereinbefore set forth. After preparation of the alumina-fluorinepills, the batch was divided into two portions. One portion of the pillswas impregnated with chloroplatinic acid-ammonium hydroxide solution andthe other portion of the pills wasim- -13 pregnated with chloroplatim'cacid solutioniree from ammonium hydroxide. After final calcination at932 F., hydrogen sulfide was separately passed through each of the twoportions and the catalyst :pills were split in half. The pillsimpregnated in the presence of ammonium hydroxide solution were of auniform grayish color throughout. The pills impregnated in the absenceof ammonium hydroxide solution were a grayish color on the outside butwere of a lighter color in the center. This illustrates that the pillsimpregnated with ammonium hydroxide solution contained the platinumevenly distributed throughout and that the pills impregnated in theabsence of ammonium hydroxide solution resulted only in surface coating.

EXAMPLE V A In order to show the eflect of fluoride ions inalumina-platinum catalysts, two separate catalysts were prepared, one tocontain no fluorine and the other to contain 1.5% fluorine. Thesecatalysts were used in separate runs for reforming a Pennsylvaniastraight-run naphtha :having an F2 octane number of 41.8, at atemperature of 874 F., pressure of 500 pounds-per square inch and aweight hourlyspace velocity of about 2. The results are shown in thefollowing table.

Table IV Catalyst 9, Catalyst containing fluorine Catalyst 8, Nofluorine in catalyst Liquid volume yield percent of charge.. 06. 82. F2,octane number": .l--. 59.8 78.8

It will be noted that the catalyst containing fluorine yielded areformate of 19' octane numbers higher than the catalyst containing nofluorine.

EXAMPLE VI This example illustrates the arrest of different amounts offlourine in the alumina-platinum catalysts. These catalysts wereprepared to contain 1.5%, 3% and 6% fluorine and'wereused for thereformingof the same gasolinedescribed in Example V and under the sameconditions of operation except that the temperature was varied as shownin the following table. a

Table v Catalyst 10, 1.5% fluorine Catalyst 11, 3% fluorine Reformingtemperature, F"

Reformate yield, weight percent of charge F2 octane numberflhl It willbe noted that the catalyst containing 1.5% and 3% fluorine gaveoctanenumbers of 78.8 and 77A and yields of 83.2% and 85% respectively,whereas the catalyst containing 6% fluorine gave a much lower yield anda lower octane number gasoline.

EXALAPLE V II were used for the separate reforming of a.

be! products. 7 should not be increased above about 8% and 7 Penn-'sylvania straight-run naphtha having a boiling range of from 219 to 339F. and an F2 octane number of 41.2. The reforming was effected at v 872F., 500 pounds and a space velocity of about 2. The results of theseruns are shownin the following table.

Table VI Catalyst Catalyst Catalyst 13, 0.5% 14, 1.5% 15, 3.5% chlorinechlorine chlorine Liquid volume yield, Weight I percent of charge 92. 380. 5 93. 4 F2,-o'ctane number 64.2 g 74.6 76- It will benoted that thecatalyst containing 0.5% chlorine produced a reformate of 64.2 octanenumber. Therefore, the chloride content of the catalyst preferably isnot below about 0.5% and certainly not below about 0.2%. Catalysts No. 8and No. 9 containing higher concentrations of chlorine produced higheroctane num- However, the chlorine content preferably not above about 5%because the catalystv will produce excessive hydrocracking and result inan excess of gas formation.

EXAMPLE VIII about 2. The results of these runs are shown in thefollowing table.

Table VII are gg platinumalumina ma Liquid volume yield percent ofcharge"..- 81.6 99 F2 octane number 80 y 50. 6

It will be noted that the catalyst containing no platinum yielded aproduct of 50.6 octane number, whereas the platinum-containing catalystyielded a product of 80 octane number.

The effect of chlorine content on the catalyst as shown in this example,wherein three different catalysts comprising 0.1% platinum on aluminawere prepared to contain 0.5%, 1.5 and 3.5% chlorine in the finalcatalyst. These catalysts It is readily apparent that the 0.1% by weightof platinum exerts a definite catalytic effect; \Iclaim as myinvention: 1. A method of manufacturing a catalyst whic comprisescombining a halogen with alumina in an amount of from about0.1 to about8% by weight of said alumina on a dry basis, forming the alumina intoparticles of uniform size and shape, calcining said particles at atemperature 'of from about 1000 to about 1400F., commingling with thecalcined particles a platinum compound-ammonium hydroxide solution in anamount to form a final catalyst containing from about 0.01 to about 1%by weight'of platinum;

and heating the composite at a temperature of from about 500 to about1000 F.

2. The method of claim 1 further characterized in that said halogencomprises fluorine in an amount of, from aboutv 0.1; to about 3%byweight of alumina on a dry basis.

3,,The method of claim 1 further characterized in that said halogencomprises chlorine inan amount of from about 0.2 toabout 8% by weight ofthe alumina on a dry basis.

4. A method of preparing a catalyst which comprises precipitatingalumina from aluminum chloride, washing to remove chloride ions to belowabout 0.1% by weight of said alumina, combinins fluorine with thealumina in an amount of from'about 0.1 to about 3% by weight of saidalumina, forming the composite into particles of uniform size and shape,calcining the particles at a temperature of from about 1000 to about1400 F. commingling with the calcined particles a platinumcompound-ammonium hydroxide solution in an amount to form a finalcatalyst containing from about 0.01% to about 1%, byweight of platinum,and heating the composite at a temperature of from about 500 to about1000 F.

' 5. A method of manufacturing a catalyst which comprises precipitatingalumina from aluminum chloride, washing to remove chloride ions to belowabout 0.1% by weight of said alumina, adding a dilute aqueous solutionof hydrogen fluoride to said alumina in an amount to form a finalcatalyst containing from about 0.1 to about 3% by Weight of fluorinebased on said alumina, pelleting the composite. to form pills of uniformsize and shape, calcining the pills at a temperature of from about 1000to about 1400" F., commingling with said pills a platinum.compound-ammonium hydroxide solution having; a pH of from aboutto about10 in an amount to form a final catalyst containing from about 0.01 toabout 1% byweight of platinum, and calcining the final composite in airat a temperature of from about 500 to about 1000 F.

'6. The method of claim 5 further characterized in that said platinumcompound-ammonium hythe alumina. to. form pills of uniform size andshape, calcining the pills at a temperature of from. about. 1000 toabout 1400" adding a dilute aqueous. solution of. hydrogen fluoride tosaid pills in an amount to form a final catalyst containing from about0.1 to about 3% by weight of fluorine based on said alumina, comminglingwith the calcined pills a platinum compoundeammonium hydroxide. solutionhaving a pH of from about 5 to about 10 in an amount toform a finalcatalyst containing fromabout 0.01 to. about 1% by weight of p1atinum,and calcining the composite in air at a temperatureof'f-rom about500 toabout 1000 F.

8-. A method of preparing a catalyst which comprises precipitatingalumina from. aluminum chloride, washing with water containing. ammoniumhydroxide to removecchloride ions to below about 0.1% by weightofsaidalumina, adding. a dilute aqueous solution of hydrogen fluoride to saidalumina in an amount to; form a final cat-- alyst containing from about0 1% to about, 3.1% by weight of fluorine-based on said alumina,drying-the composite to a moisture content of about 30%, grinding themass'and'adding a lubricant, pelleting to form cylindrical pills,calcining at a temperature of from about 1000. to. about. 1400 E},commingling withthe calcined pills a. plati:

num compound-ammonium. hydroxide solution having a pH oi fromabout5 toabout 9 in an amount. to form a final catalyst containing. fromabout-0.01 to about. 1% by weightof platinum by soaking the aluminapills in said platinum compound-ammonium hydroxide solution,thereafter-heating to evaporate water andresidual. am.- moniumhydroxide, andfinally calcining the com.- posite. in airv at atemperature of firom about 500 to. about1000 F.

9-. The method of claim 8 further. characterizedin that said compositeisreduced in. the pres.- ence. of hydrogen at a temperature. of from.about 500 to about 10.00 F. prior to said calcining in air. I

10. A process for reforming: a gasoline fraction which comprisessubjecting said fraction to contact at reforming conditions with acatalyst prepared by combining a halogen with alumina in an amount offrom about 0.1 to about 8% by weight ofsaid alumina on a dry basis,forming the alumina into particles of uniform size and shape, calciningsaid particles at a temperature of from. about 1000. .to about 1400* F.,comminglingwith the calcined particles a platinum compoundrammoniumhydroxide solution in an amount to form a final catalyst containingvfrom about 0.01 to about 1% by weight of platinum and heating thecomposite at a temperature of from about 500 to about 1000 F.

11. A process for reforming a saturated gasolinefraction which comprisessubjecting said fraction'to' contact at reforming conditions with acatalyst prepared by precipitating alumina from aluminum chloride,washing to remove chloride ions 'to below about 0.1% by weight of saidalumina, combining fluorine with the alumina in an amount of from about0.1% to about 8% by weight of said alumina on a dry basis, forming thealumina into particles of' uniform size and shape, calcining saidparticles at a temperature of from about 1000 to about 1400" F.,commingling with the calcined particles at platinum compound-ammoniumhydroxide solution in an amount to form a final catalyst containing fromabout.0.0.1. to about 1% by weight of, platinum and. heatingthe'composi'te. inair at atemperature. of from about 500 to about 1000F;

1-2. Aprocess for reforming a. straight-rungasoline which. comprisessubjecting saidfraction to contact at a temperature. of from. about. 500to about 1000 F., a pressure. ofirom about 50. to about 1000 pounds persquare inch and a weight hourly space velocity of-from about 0.5 toabout 10, in the presence of from about 0.5 to about 10 mole of hydrogenper moll of hydrocarbon, with a. catalyst prepared by precipitatingalumina from aluminum chloride, washing to remove chlo ride ions tobelow about 011% by weight of said alumina, combining. fluorine with thealumina in an amount of from about 0.1% toabout: 3% by weight of saidalumina on a dry basis, formingthe composite into. particles of uniformsize andshape, calcining. the particles at a tempera,- ture offrom.about1000f to-about1400f FF., commingling therewith a v platinum.compound-ammonium hydroxide solution in an. amount to form a finalcatalyst containing from about 0.01 to about 1% by weight of platinumand heating the composite in airat a: temperature of from about 500 toabout 1000 F;

V 13-. In. the manufacture-of a platinum-alumina catalyst wherein'ahalogan is combined with alumina in: an amount of from about 0.1 toabout weight of the alumina ona drybasisand the alumina is impregnatedwith a platinumcontaining solution in an amount to form a final catalystcontaining from about 0.01 to about 1% by weight of platinum, the methodwhich comprises forming the halogen-containing alumina into particles ofuniform size and shape, calcining said particles at a temperature offrom about 1000 to about 1400" F., impregnating the calcined particleswith a solution of a platinum compound in the presence of ammoniumhydroxide, and heating the thus impregnated particles at a temperatureof from about 500 to about 1000 F.

14. In the manufacture of a catalyst comprising platinum, alumina and acombined halogen in an amount of from about 0.1 to about 8% by weight ofthe alumina on a dry basis, wherein the alumina is impregnated with aplatinum-containing solution in an amount to form a final catalystcontaining from 0.01% to 1% by weight of platinum, the method whichcomprises forming the alumina into particles of uniform size and shape,calcining said particles, impregnating the calcined particles with asolution of a platinum compound in the presence of ammonium hydroxide,and calcining the thus impregnated particles at a temperature notsubstantially in excess of about 1000 F.

15. A method of manufacturing a catalyst which comprises combining ahalogen with alumina in an amount of from about 0.1 to about 8% byweight of the alumina on a dry basis, forming REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 612,614 Porter Oct. 18, 18981,956,585 Oglesby et a1. May 1, 1934 2,366,126 Pines et a1. Dec. 26,1944 2,435,443 Ipatiefi et a1. Feb. 3,1948 2,461,959 Brandon Feb. 15,1949 2,475,155 Rosenblatt July 5, 1949 2,479,109 Haensel Aug. 16, 19492,479,110 Haensel Aug. 16, 1949 2,486,361 Nahin et a1. Oct. 25, 1949OTHER REFERENCES Parkes, Mellors Modern Inorganic Chemis try, pages841-845, 1939 Ed, Longmans, Green and 00., New York.

Komarwsky et al., The Oil and Gas Journal, June 24, 1943, pp. 90-93inclusive and p. 119.

10. A PROCESS FOR REFORMING A GASOLINE FRACTION WHICH COMPRISESSUBJECTING SAID FRACTION TO CONTACT AT REFORMING CONDITIONS WITH ACATALYST PREPARED BY COMBINING A HALOGEN WITH ALUMINA IN AN AMOUNT OFFROM ABOUT 0.1 TO ABOUT 8% BY WEIGHT OF SAID ALUMINA ON A DRY BASIS,FORMING THE ALUMINA INTO PARTICLES OF UNIFORM SIZE AND SHAPE, CALCININGSAID PARTICLES AT A TEMPERATURE OF FROM ABOUT 1000* TO ABOUT 1400* F.,COMMINGLING WITH THE CALCINED PARTICLES A PLATINUM COMPOUND-AMMONIUMHYDROXIDE SOLUTION IN AN AMOUNT TO FORM A FINAL CATALYST CONTAINING FROMABOUT 0.01 TO ABOUT 1% BY WEIGHT OF PLATINUM AND HEATING THE COMPOSITEAT A TEMPERATURE OF FROM ABOUT 500* TO ABOUT 1000* F.